1. Field of Invention
This invention relates to a small, low cost device for the mechanical sealing of pressure sensitive glue treated material, specifically business forms, used as "self-mailing"pieces. The machine can be used "off line" as a stand-alone device for sealing small runs of forms, either as a back up for other larger pressure sealing machines, or as the primary sealer for small businesses. The machine can also be used in conjunction with separate forms folding device for a more automated system.
2. Description of Prior Art
Until now the cost of pressure sensitive self-mailer forms has limited the market to large volume users. The majority of equipment design has consequently been for high-speed heavy-duty applications. With the advent of competition in the manufacture of pressure sensitive forms, prices per form are now within the range of small volume users. The problem to date in getting small users into pressure seal product has been the high cost of the equipment necessary to seal the product.
In addition, a market exists for a back up or emergency machine for existing users of pressure seal forms if their primary sealer is broken, while waiting for service. While users of water activated adhesives can manually apply water via sponges to their documents and users of heat sensitive adhesive can actually "iron" them with an electric iron until service is restored, pressure seal users have no back-up alternative.
U.S. Pat. No. 5,540,806 to Traise (1995) discloses a "table-top" sealer for low speed, low volume applications, which utilizes narrow edge rollers and a complex pivoting yoke mechanism.
U.S. Pat. No. 5,656,118 to Traise (1997) an improvement to U.S. Pat. No. 5,540,806 still utilizes narrow edge sealing rollers with a cumbersome method of removing and replacing different size bolts to activate/deactivate the sealing pressure.
U.S. Pat. No. 5,183,527 to Parker (1993) is a portable "perimeter" pressure sealer, also utilizing narrow edge wheels that seal only the edges of a document.
U.S. Pat. No. 5,133,828 (1991) and U.S. Pat. No. 5,211,793 to Jacques (1993) still utilize an edge only sealing method with the addition of complex electronics to reverse motor direction, moving the form forward and back within the sealer.
U.S. Pat. No. 5,772,841 to Lindsay (1998) details an "in-line" pressure sealing machine that utilizes two sets of biased rollers to effect product seal. The machine seals the product, which is fed through in the shorter width orientation as delivered from a form folder in line with the sealer.
While some of the features of these patents are unique, nevertheless they all suffer from several disadvantages:
The small units only seal the edges of the document, one side at a time. PA1 The small units require that the form be reinserted in the sealer to seal the opposite edges either manually or through a complicated electronic method. PA1 They are expensive to manufacture and consequently expensive to purchase. PA1 They all require complicated adjustments to control sealing roll pressure or relief. PA1 (a) To provide a pressure sealing device that is mechanically simple and very low cost to manufacture; PA1 (b) To provide a pressure sealer that seals the entire document in one pass. PA1 (c) To provide a pressure sealer that can be used as a stand-alone unit or used in conjunction with any commercial form folder. PA1 (d) To provide a pressure sealer that requires no adjustments to pressure or relief rollers.